Missing `mounts:` no longer defaults to mounting home directory

[cflee]

Description

When starting up a colima.yaml without a mounts: key, it does not default to mounting the user's home directory as documented in the config file.

The config is also updated to mounts: null instead of the documented default of mounts: [].

Version

colima version 0.10.1
git commit: ed90520

runtime: docker
arch: aarch64
client: v29.2.1
server: v29.2.1
limactl version 2.0.3
zsh: command not found: qemu-img

Operating System

• macOS Intel <= 13 (Ventura)
• macOS Intel >= 14 (Sonoma)
• Apple Silicon <= 13 (Ventura)
• Apple Silicon >= 14 (Sonoma)
• Linux

Output of colima status

INFO[0000] colima is running using macOS Virtualization.Framework
INFO[0000] arch: aarch64
INFO[0000] runtime: docker
INFO[0000] mountType: virtiofs
INFO[0000] docker socket: unix:///Users/cflee/.colima/default/docker.sock
INFO[0000] containerd socket: unix:///Users/cflee/.colima/default/containerd.sock

Reproduction Steps

1. Write or modify the default instance's colima.yaml to have no mounts: line
2. Run colima start
3. Run colima ssh and ls to observe that the home directory is not mounted
4. Read the colima.yaml and observe that it reflects mounts: null
5. Run colima restart
6. Run colima ssh and ls to observe that the home directory is still not mounted

Expected behaviour

Upon colima start, when mounts: is not stated, the home directory should be mounted matching the behaviour stated in the config file, and the config file should be updated to mounts: [] (and that should have this behaviour).

# Colima default behaviour: $HOME is mounted as writable.
# Default: []

Additional context

I suspect this is a regression in v0.10.0 from #1485 as the condition for mounting the user's home directory was updated from len(conf.Mounts) == 0 (would be true where the mounts key is missing as it's unmarshaled into a nil slice that has len 0) to conf.Mounts != nil && len(conf.Mounts) == 0 (would be false as it's a nil slice)

[lucidNTR]

i would like to point out that defaulting to mounting home was HORRIBLE security and user experience, a vm should never ever ever mount my private stuff as default. Maybe just update the readme and do the responsible thing?

[abiosoft]

When starting up a colima.yaml without a mounts: key, it does not default to mounting the user's home directory as documented in the config file.

@cflee you can set mounts: [] if you want the previous behaviour. The new behaviour was introduced in v0.10.0.
Having no mounts key is equivalent to mounts: null, and that would disable mounts entirely.

The readme would be updated to reflect the new behaviour.

i would like to point out that defaulting to mounting home was HORRIBLE security and user experience, a vm should never ever ever mount my private stuff as default. Maybe just update the readme and do the responsible thing?

@lucidNTR I would reiterate again that this is the norm for the expected docker experience. Docker Desktop still does that till date.
If Colima is not transparent and there is no easy way to access the VM (like with Docker Desktop), you would probably not have an idea.

You can argue that Colima does more than "just docker" and has a slightly different audience to Docker Desktop. I agree and we can all collaborate to arrive at an experience that suits most users.

Thanks.

[cflee]

Having no mounts key is equivalent to mounts: null, and that would disable mounts entirely.

The readme would be updated to reflect the new behaviour.

I see, so it's not a bug, I just didn't expect this as part of the "Volume mounts can now be disabled by passing --mount=none to colima start." change in v0.10.0.

Could I suggest that the comments in the default colima.yaml be updated as well, as when I see those comments during colima start --edit I took the description there to be authoritative about how the option is working. Thank you!